Mold for casting metals



Patented ar. 15, 1927..

WILLIAM E. SMITH, OF DETRDIT, MICHIGAN, ASSIGNOR T FGRD MOTOR COMPANY, 61 HIGHLAND FARE, MICHIGAN, A CORPORATION OF DELAWARE.

llJIClIIIiIE-I FOR CASTING METALS.

: No Drawing.

The -ob'ect of my invention is to provide a mold o the so-called permanent type for the casting of molten metals. 1 am aware that it has been proposed heretotore to make 5 molds from cast iron or metallic compositions and their oxides. I am also aware that attempts have been made to coat such molds H with compounds of oxides in the endeavour to prolong the life of the mold. Practice has l0 shown that no combination of metals or oxides have withstood the strains of the irregular expansions of such elements used, and contraction strains applied to the mold from the cooling and solidifying changes of the {5 metal cast.

It is the object of my invention to produce a metallic mold which will withstand the heat changes and strains to which each mold will be subjected in practical use Without ex- 59 cessive deterioration. With my mold I am able to secure a longer life and greater production and a more uniform casting than has I heretofore been obtained. In practical operation I have used molds made of substantially pure iron, that is, iron having no other elements in association or combination of morethan one per cent. I attribute my succ'ess with such mold to the fact that in the Application filed August It, 1925. serial No. 50,812.

case of cast iron or steel mold that such mold having elements in combination of over one per cent a different ratio of expansion and contraction takes place in the mold through the deficient ratios of heat changes of the elements comprising the mold such heat changes causing strains and breakage of mold. My practice has shown that in .the use of iron containing less than one per cent of foreign substances the'expansion and contraction is more uniform throughout than where iron having relatively more foreign substances is used. Therefore irregular strains are not set up in the mold to cause breakingdown of its structure, resulting in a longer life than has heretofore been obtained in the use of molds for molten metal.

I have used an iron which is known to the trade as Armco, manufactured by the American Iron Company, very satisfactorily for molds to be used'in accordance with my in vention.

I claim as my invention: 1

A metallic mold for hot metal casting made from iron having no other element or elementsin its makeup over one per cent.

-WILLIAM sMrrn. 

